I first enabled icon on folder tab in 9.11RC1 icon stay blank, in my 4K monitor.

(Also for 9.10)
On another computer, I do not get icon for folder, as the one i see in file panel. (i did not defined any icon at default custom view nor using folder properties ) and checked all options...

-- Edited
with fresh install, i got drive icon and custom view icon (if i define some) with 9.11RC1. No folder icon, I also did not find what is causing icon to not show-up even for drive with my standard install. Space is there but icon not drawn